A
Day in the Life of a Migrating Whooper
Brian Johns, Canadian Wildlife Service
|
Brian
Johns, CWS |
How
High Do They Fly?
Whooping
cranes migrate anywhere from 15 metres to 1800 metres above the ground.
Most often their flights are around 500 metres, making them
visible from the ground. Occasionally people on the ground will see
them migrating, but most observations come from people who observe
them at stopover locations where the Whoopers are resting or feeding.
How
Fast? How Far?
When migrating,
Whooping Cranes can fly at speeds of anywhere from 60 - 80 kilometres
per hour (kph) or more. If they have a tail wind, the birds
can reach speeds of over 100 kph. Daily distancess average
around 400 kilometres and the birds stay aloft for 7 or more hours.
In spring, crane flights as long as 650 kilometres in
length and flying times of 8 to 10 hours have
been recorded. How are the birds able to fly so long in a
day?
Read on! |
|
Subadult
Whooping Cranes Soaring and Gliding.
Photo WCEP |
Soaring
and Gliding
Cranes are unlike most other birds when they migrate in that
they flap their wings very little. When the cranes take off from the
ground around mid-day, they begin flapping until they find a thermal
of warm air rising from the ground. The birds will then circle in the
thermal to gain altitude. Once they have reached the top of the thermal
they will set their wings and glide in the direction of migration,
slowly descending along the way. When they reach another thermal,
they will
again spiral upwards. They repeat the process over and over throughout
the day.
A
thermal is a column of rising air caused by uneven heating
of
the earth. |
|
Cumulous
clouds are tell-tale signs of thermals. |
Coming
Down for the Night
Towards the end of the day, the cranes will begin to look for a suitable
place to spend the night. Suitable places include shallow wetlands surrounded
by good feeding areas. Once they find a likely-looking spot, they will
slowly glide down to spend the night, roosting
in the shallow water.
Journal
or Discuss: Migration Metrics